Salinity-gradient energy, also referred to as “blue energy”, exists in estuaries when freshwater and seawater mix. Globally, the potential blue energy from mixing river water with seawater is estimated at about 2 TW. Different technologies have been proposed to recover this untapped energy source, including a mixing entropy battery (MEB).
A proposed MEB is demonstrated to recover electricity from seawater and wastewater effluent at an efficiency of about 68%. However, the high cost of electrode materials used, as well as an energy investment during a charge step, made the MEB less practical for full-scale applications. Therefore, a need exists for an improved, low-cost MEB that omits a charge step and reduces an upfront energy investment.
It is against this background that a need arose to develop the embodiments described in this disclosure.